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5 Easy Ways to Straighten Warped Wood

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If you are a professional woodworker or a DIY enthusiast working with wood, you may have come across wood with grains that are not straight. Accuracy is paramount when working with wood, whether you’re cutting the wood or nailing them together.

Warping can affect the shape and form of the finished product in a lot of ways. If you want to avoid the challenges of working with warped wood, you have to try to prevent the wood from warping or straightening already warped wood. However, not many people know how to do this; this is why a guide like this showing you how to straighten the wood grains is vital.

What is Wood Warping?

What is Wood Warping
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Wood warping is when the wood is bent due to the curling of its grains. When this happens, the wood is no longer straight and affects your finished project. Typically, moisture content and the change at a given time is the primary reason for wood warping. However, there are so many causes of wood warping.

Read More: What is Parawood? Here’s All You Need to Know

Causes of Wood Warping

Causes of Wood Warping
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As earlier mentioned, the major reason a wood warps is because the moisture level in the wood changes too slowly or too quickly. However, here are some other reasons why your wood will warp.

1. Exposure to Heat

When wood is exposed to heat over a long period, its grains experience stress which causes an expansion between its molecules which forces the wood apart and warps.

2. Exposure to Moisture Content

If wood is exposed to moisture and absorbs it in an irregular pattern, the wood can get warped and bent. When water is absorbed, it dries out in an irregular pattern which causes some parts to bend.

3. Poor Wood Quality

Poor Wood Quality
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A low-quality wood is prone to warping as they are easily affected by external forces. Low-quality wood is not always the cheapest available. Their quality depends on their source and how they are cut, among other things.

4. Insects

Insects may seem like an unlikely cause of wood warping, but they can attack the fiber of the wood and cause it to bend. Insects like ants and beetles are the most common as they bore into the wood and clear out a large chunk in a short while.

5. Wrong Storage

When wood is stored wrongly, it can lead to warping. Typically, when the wood is stood upright in storage without any support throughout its length, it tends to warp as the fiber tries to stabilize itself.

Types of Warping

There are several ways your wood can warp, and knowing the type of warp on your wood is the first step to straightening the wood.

1. Kink

Kink is a common type of warping that happens when one part of the wood called slat is warped. It occurs when the wood is exposed to a lot of moisture or heat. Kinking can be found at the edge of the wood, where you’ll notice a 45 degrees bend.

2. Bow

Bow is another common type of warping where the surface of the wood sees an inward or backward bend. When wood is placed on a flat surface and exposed to heat and or moisture, bow warping can occur.

3. Cup

This type of warping is not as common as the two above; however, they are just as detrimental. Cup warping happens along the long edges. Typically, these edges curve inwards towards the slat face. This is common with woods with thin edges and wide faces.

4. Twist

Twist warping usually happens during storage when woods are not kept properly. Your wood can also be twist-warped if the water absorbed does not dry out evenly. This warping occurs on longer boards, with the ends seeing a twisting form.

How to Straighten Warped Wood?

How to Straighten Warped Wood
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If you notice your wood is not straight due to warping, even on the tiniest of spots, care needs to be taken to remove this bend and prevent it from spreading. While more than a couple of woodworkers know straightening warped wood is possible, only a few know how to do it. So, here are some ways to straighten that bent wooden plank or log so you can get the perfect finished project.

1. Moisture and Steam

One of the most common ways of unwarping wood is by using the moisture and steam method. In the same way, moisture and heat cause wood to warp; you can use the two to unwarp wood.

Heat the wood lightly for ten to fifteen minutes, and then add even more moisture to the wood. The heat will allow the wood to absorb more moisture.

With this, the wood would be flexible and can be bent back into shape. Straighten the bent areas and clamp them to a flat surface, so it dries straight. This method is especially helpful when dealing with bow warps.

2. Sunlight

Using the power of the sunlight, you can straighten warped wood easily. However, this method takes a lot of time and is not recommended if you cannot be patient enough since it is usually a slow process. This method of unwarping wood has been in existence for a long time and makes use of a towel and moisture.

Soak the towel in water and then squeeze to remove excess water. Wrap the warped wood with a damp towel and place it under the sun. Allow the sun to hit it for up to four days to straighten the wood and remove the warp. This method is more effective for kink warps.

3. Pressure

You can remove warp from wood by applying pressure in the right places and over a long time. This is also a slow procedure and should only be practiced by people with enough patience. Place damp paper towels on the surface of the area affected by the warp and wrap the wood with plastic to ensure the moisture does not touch other areas.

After a while, remove the plastic covering the board and then place the wood on a table or any flat surface. Clamp the board down and then apply heat to the warped area. Allow it to straighten over several days before removing the clamp.

4. Jack Plane

This type of unwarping method is quite effective when dealing with cup warps on wood with thick edges. Jack planing involves removing part of the bent area with the jack plane, which then straightens the surface. However, you have to be careful, so you don’t remove a large part of the wood and weaken it.

5. Iron

A pressing iron is one unorthodox but effective way of straightening warped wood. Your pressing iron, a wet piece of cloth/towel, and an ironing table are all you need for this method which makes it relatively easy to do.

Soak the towel in water and squeeze out excess water, so it is only damp. Cover the whole warped surface area and place it on your ironing table. Heat your iron and keep on pressing the towel. Do this continuously until the wood straightens; you can then clamp it to the ironing board and allow it to dry.

How to Prevent Wood Warping?

How to Prevent Wood Warping
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You can wait till the wood is warped and then try to straighten it out, which is stressful, time-consuming, and sometimes even ineffective, or you can try a preventive method. A preventive method will stop the wood from warping in the first place, so you don’t have to bother about straightening it out. There are a couple of ways of preventing warping.

1. Proper Storage

Oftentimes, improper storage is the cause of wood warping. So if you want to prevent the wood from bending, you can start by storing it properly by laying it flat instead of standing it. If you must stand it, you have to provide support along its full length. While storing it flat, ensure you stack it according to size to have stacks for each size.

2. Inspect Wood Before Buying

Poor quality wood is prone to warping, and this is why you want to inspect the wood carefully before buying. You also want to ensure the wood has not started warping. Avoid wood with obvious moisture content in it, and make use of a moisture content detector where possible to know the moisture level in the wood.

3. Coat the Wood to Make it Moisture Proof

Water and heat are responsible for warping, so if you can make your wood moisture-proof, you can significantly reduce the chances of getting warped wood.

One surefire way to do this is by coating the surface of the wood with a finish like polyurethane or oil-based paints that can insulate the surface of the wood and prevent water and heat from affecting the wood.

The good thing about this method is that it also increases the aesthetics and durability of the wood.

4. Do not Completely Dry Out the Wood

When wood is completely dry, it can cause warping as quick evaporation as well as slow evaporation causes wood to bend. You want to maintain a tiny amount of water or simply not completely dry the wood, so the fibers do not bristle and are quick to turn.

Also Read: How To Distress Wood? 11 Easy Ways For Woodworkers

Tips for Straightening Warped Wood

Here are tips and techniques that’ll make the process of unwarping wood easier and more effective:

  • Wear protective gloves that are heat resistant, especially when using any of the methods involving heat.
  • Have some patience as some of the methods of unwarping wood takes a lot of time, sometimes days to work. You may also have to redo some of the processes to completely straighten the wood. Patience will ensure you do not get frustrated during this process.
  • Know the type of warp first before attempting to straighten the wood. This will help you choose the right method and improve your chances of getting results.


Wood needs utmost care if you want to see a straight and aesthetically pleasing finished project. Wood warping is a major concern for woodworkers, but straightening it can be done easily with the right steps.